chg: [docs] Version bump of OpenBSD to 6.4
chg: [docs] Version bump of OpenBSD to 6.4

FIRSTdotorg/MISP,devnull-/MISP,MISP/MISP,SteveClement/MISP,devnull-/MISP,FloatingGhost/MISP,devnull-/MISP,FIRSTdotorg/MISP,FloatingGhost/MISP,SteveClement/MISP,FloatingGhost/MISP,MISP/MISP,Rafiot/MISP,SteveClement/MISP,MISP/MISP,MISP/MISP,SteveClement/MISP,Rafiot/MISP,FIRSTdotorg/MISP,FIRSTdotorg/MISP,FloatingGhost/MISP,devnull-/MISP,MISP/MISP,SteveClement/MISP,Rafiot/MISP,Rafiot/MISP